Polyamide color formers



Patented Sept. 30, 1947 UNITED STATES PATENT OFFICE POLYAMIDE COLOR FORMERS David Malcolm McQueen, Wilmington, Del., as-

slgnor to E. I. du Pont de Nemours a Company, Wilmington, Del., a corporation of Delaware No Drawing.

Original application March 31, 1944, Serial No. 528,944.

Divided and this application February 24, 1945, Serial No. 579,693

7 Claims. (01. 260-310) 1 This invention relates to hydrophilic dye intermediate polymers. More particularly, it relates to novel hydrophilic polyamides containing a plurality of solubilizing groups and dye intermediate nuclei.

This application is a division of application Serial No. 528,944, filed March 31, 1944, which has been issued as Patent No. 2,423,460, July 8, 1947.

An object of this invention is to provide new color-yielding compositions comprising hydrophilic polymers having dye intermediate nuclei. A further object is to provide hydrophilic dye intermediates which may be used as binding agents for silver halides.. Still other objects will be apparent from the following description of the invention.

The present invention involves the preparation and use of hydrophilic polyamide dye intermediates which are synthetic linear polyamides containing a plurality. of solubilizing groups and a plurality of dye intermediate or color-forming nuclei. The polyamides contain a plurality of intralinear polyamide linkages and a plurality of ether, hydroxyl, or salt-forming groups as an integral part of the polymers and a plurality of dye intermediate or color-forming nuclei. The polyamides are hydrophilic .because of the presence of such groups but their properties can be modified by the incorporation of solubilizing groups into the dye intermediate nuclei or by the pable of coupling with a diazo compound to form incorporation of insolubilizing groups or radicals into the polymer molecule.

The solubilizing groups may be present as intralinear groups or atoms. e. g., lntraiinear ether (-0-) or amino (-NR,-) groups or as lateral or side chain substituents, e. g., hydroxyl groups, ether groups -OR., and amino groups wherein R. is a hydrocarbon radical, e. g., methyl. ethyl, etc., or a hydrocarbon radical containing salt-forming groups, e. g., COOH, SOaH, etc. These new polyamides form homogeneous unsupported films which are hydrophilic and permeable to aqueous photographic developer, fixing, bleaching, etc., solutions. The layers, moreover, are substantially colorless and transparent. The term "hydrophilic as used in this application and claims, when referring to the dye intermediates, etc., is intended to denote compounds which in the form of thin layers, e. g.,

an azo dye. Such nuclei are usually'also capae, ble of coupling with the oxidation products of a color coupling aromatic primary amino developing agent formed on the development of silver salt images to form a quinoneimine (including indamine, indoaniline and indophenol) dye or an azomethine dye.

Nuclei of the above type are well known in the dye art and color photography art. They are sometimes called color-former components, dye-coupling components, etc.

These dye intermediate nuclei have as the active coupling groups a structure which may be represented as where X is H0 or RNH, where R is hydrogen or a saturated aliphatic group, e. g., methyl, ethyl, beta-hydroxyethyl, beta-chloroethyl, benzyl, dodecyl, etc., and n is 0 or 1. This group is found in the reactive methylene dye intermediates and in aromatic hydroxyl and amino compounds and includes the reactive ethenol, aminoethenyl, e-hydroxyand 4-ar'nino-1,3-butadienyl groups. These groups occur in phenols, naphthols, anilines, naphthylamines, acylacetamides, cyanoacetamides, beta-ketoesters, pyrazolones, homophthalimides, coumarones, indoxyls, thioindoxyls, etc.

The reactive ethenol group represented by occurs in phenols and naphthols which couple in the ortho position and in the alkali soluble or enol form Olf most reactive methylene dye intermediates. These reactive methylene groups have a hydrogen rendered mobile by the proximity of certain unsaturated groups such as, for example,

CEN and others. The CH2-- group is usually present between two such groups, for example,

COCI-IzC=N- in a cyclic or acyclic system.

The reactive aminoethenyl group,

' RH-N-c=dn occurs in aromatic amino compounds which couple in the ortho position.

The 4-hydroxyand 4-amino-L3-butadienyl groups represented as occur in phenolic, naphtholic and aromatic amino compounds which couple in the para (4) position.

In all of these dye intermediate groups the hydrogen atom in the coupling reactive position may be replaced by groups readily eliminated in the coupling reaction, e. g., halogen, sulfonic acid, carboxylic acid, etc.

The term synthetic linear polyamide" as used in the present invention refers to the polymeric condensation products containing recurring amide linkages which can be derived from (1) monoamino monocarboxylic acids, (2) diamines with dibasic carboxylic acids, or (3) interpolymers of amino carboxylic acids with diamines and dibasic carboxylic acids. Amide-forming derivatives of these bifunctional reactants may also be employed. General methods for preparing such condensation olymers are described in U. 8. Patent 2,071,250. The polyamides suitable for this invention should contain at least one amide group to every 22 atoms of the polymer chain, and preferably at least 1 solubilizing group for every 40 atoms of the polymer chain. The polyamides, moreover, are highly polymeric and should have a unit length of at least 20 where "unit length" is defined as in U. S. Patents 2,071,- 253 and 2,130,948. Y

The preferred polyamides for use in preparing the hydrophilic dye intermediates of this invention have an intrinsic viscosity of above 0.4 where intrinsic viscosity is defined as log, N r 6' wherein Nr is the viscosity of a dilute, metacresol solution divided by the viscosity of metacresol in the some units and at the same temperature, and C is the concentration in grams of polyamide per 100 units of solution. They have a high softening point when dry. The preferred hydrophiiic color-forming polyamides are soluble to the extent of at least parts of boiling water or a boiling mixture of water containing less than 50% of a water-miscible solvent and preferably less than 25% of ethanol.

To secure this degree of solubility, it is necessary to choose the polyamides used for preparing the hydrophilic film-forming polyamides from among those products which possess the requisite solubility in aqueous solutions or to introduce solubilizing groups into products of insuihcient solubility. Polyamides of the requisite solubility which contain a plurality of intralinear hetero atoms such as oxygen and amino nitrogen atoms are described in U. S. Patents 2,158,064 and 2,191,556. Other useful polyamides of the proper solubility containing several solubilizing components are described in U. S. Patents 2,285,009 and 2,320,088, A fairly wide range in the degree of solubility in aqueous solvents is provided by the use of the products of such patents as intermediate materials.

Still other useful hydrophiiic polyamides which contain hydroxyl groups, carboxymethoxy (OCH2COOH) methoxy, ethoxy, methoxyethoxy, etc., and salt-forming groups can be used. Such polyamides can be prepared by reacting a less water soluble polyamide with formaldehyde or with formaldehyde in the presence of an alcohol, e. g., ethyl, methoxyethyl, methyl, benzyl, and esters of glycolic acid, e. g., methyl glycolate, ethyl glycolate, etc. Alkaline hydrolysis of these last mentioned hydroxy ester-containing polyamides yields the desirable class of soluble polyamide-containing carboxymethoxy groups.

The introduction of dye intermediate or colorformer nuclei into the polyamides will he further described in the following exemplary procedure. A polyamide soluble in water or water-alcohol mixtures, e. g., the condensation polymer I obtained from (i) tri-glycoldiamine and sebacic acid, (2) bis-amiopropoxyethane and adipic acid, (3) hexamethylenediamine and diglycolic acid,

'(4) diaminodipropyl ether and adipic acid, (5)

hexamethylenediamineand adipic acid further reacted with formaldehyde and methanol to contain methoxymethyl groups on about 10 to 20% of the amide groups, (6) hexamethylenediamine and N-methyliminodiacetic acid, (7) hexamethylenediamine and N,N'-piperazine diacetic acid..

(8) hexamethylenediamine and adipic acid further reacted with formaldehyde and methyl glycolate to contain methoxycarboxymethoxymethyl groups on about 10 to 20% of the amide groups, is condensed in acidic medium, e. g., formic acid, with formaldehyde or formaldehyde generating compounds, e. g., paraformaldehyde, to form the methylol polyamide which is further condensed with a dye intermediate reactive with formaldehyde, e. g., a phenolic, naphtholic, or aromatic amino compound, including those containing a hydroxyl or amide group on a side chain, or an active methylene coupling component such as phenylmethylpyrazolone, acetoacetanilide, thioindoxyl, N-homophthalylamines, etc. Alternatively, the formaldehyde-reacting material may first be condensed with the dye intermediate to form the methylol derivative, e. g., o-methylclphenol, methylol phenylmethylpyrazolone, etc., which may itself be condensed with the polyamide in acidic solution.

The dye intermediate substituted hydrophiiic polyamides prepared in the above way contain dye intermediate substituted amide groups as a part of the polymer chain. These substituted amide groups have the structure I con-om-a-o tographic processing solutions at temperatures in the neighborhood of 20 0., (3) insolubility and freedom from softening in water at moderate temperatures, (4) transparency and freedom from color, (5) adequate solubility in satisfactory solvents for coating, (6) freedom from adverse action on sensitive silver salts, ('7) a relatively high softening point, and (8) ability to disperse, prevent coagulation and sedimentation of silver salts.

The following examples, in which parts are by weight, all temperatures centigrade. and all solutions aqueous unless otherwise stated, are illustrative of the nature of the invention and not intended to limit it in any way.

Example I A mixture of 20 parts of diaminodipropyl ether/adipic acid polyamide prepared by heating an equimolar mixture of diaminodipropyl ether'and adipic acid at 220 for two hours and 50 parts of formic acid is stirred at 65 until a solution is obtained; then ten parts of saligenin is added and stirring at 65 continued for-onehalf hour. Five hundred parts of acetone is added to precipitate the hydrophilic dye intermediate. The solid is removed by filtration, extracted with acetone, and dried to give 26 parts of a white powder containing approximately one o-hydroxy-benzyl group for each six amide groups. It forms a blue-green dye upon color coupling development .of silver salts with paminodiethyl aniline.

Example If A mixture of 50 parts of bis-aminopropoxyethane/adipic acid polyamide prepared by heating together at 200 an equimolar mixture of bisaminopropoxyethane and adipic acid in 100 parts of formic acid is stirred at 65 until a solution is obtained. Then 25 parts of paraformaldehyde is added and stirring at 65 continued for fifteen minutes, followed by addition of 90 parts of phenylmethylpyrazolone and stirring for thirty minutes, after which 20 parts of butanol is added and stirred for fifteen minutes. The solution is precipitatedby adding 1000 parts of acetone. The solid is removed by filtration, extracted with acetone, and dried to give 50 parts of, a white powder. This material is the mixed butyloxymethyl/phenylmethylpyrazolonoxymethyl polyamide, namely butoxymethyl/(l phenyl 3- methyl-5-pyrazolon-4-yl)methylpolyamide, having approximately one color-forming group for each eight amide groups. It yields a bright magenta dye image upon color coupling development of silver salts with p-aminodiethyl aniline. It also yields a brilliant yellow dye upon similar development with phenyl hydrazine.

Example III To a solution at 60 of parts of the triglycoldiamine/adipic acid polyamide in 50 parts of 90% formic acid is added 6 parts of paraformaldehyde and the mixture stirred at 60 for fifteen minutes; then 53 parts of acetoacetanilide is added and stirring at 60 continued for onehalf hour. The product is precipitated by addition of 500 parts of acetone, the solid removed by filtration and extracted with acetone and dried to yield 28 parts of a yellowish white powder, having color-forming units of the following probable structure: I

-NH(CH1)20(Cuzh (Cnz)2IIICO(Cn2)iC0 (llIi z cn-comrO coon: It yields a bright yellow dye image upon color coupling development of silver salt images with p-aminodiethyl aniline.

Example IV Example V A solution of 100 parts of polyhe'xamethylene adipamide (intrinsic viscosity 1.0) in 400 parts of 90% formic acid is stirred at 60. To this is added 30 parts of paraformaldehyde and. the mixture is stirred at 60 for tenminutes, then 60 parts of 1-N-hydroxethylaminonapthalene-6- sulfonic acid and 25 parts of methyl/hydroxyacetate are added and the mixture stirred for one-half hour at 60, then poured with stirring into 2000 parts of acetone and 1000 parts of water. The liquid is decanted and 1000 parts of 50% acetone water added and made alkaline by addition of ammonium hydroxide. After washing with 4 charges of 1000 parts each of 40% acetone, the produce is dried. It yields a brilliant magenta dye upon color coupling development of exposed silver salts by means of p-aminodiethyl aniline.

Example VI A solution of 30 parts of polyhexamethylene adipamide (intrinsic viscosity 1.0) in 400 parts of 90% formic acid is heated to 50 with stirring. To this solution is added 10 parts of paraformaldehyde and the mixture is stirred at 55 for 15' washed withthree changes of 500 parts each of acetone, the total wash time being 6 hours. The product is then filtered and dried to give a lightcolored powdery polyamide containing 4-chlorol-hydroxy-Z-naphthyl groups and carbomethoxymethoxy groups attached through methylene groups to the amide nitrogens of the polyamide chain.

Ten parts of this color-forming polyamide'is dissolved in 40 parts of 60% ethanol/water at 60 and 10% of sodium hydroxide is added until the solution after stirring for 5 minutes has a, pH of 9. Under these conditions, the glycolic ester groups are hydrolyzed and the polymer contains carboxymethoxymethyl sodium salt groups (NaOCOCHzOCHz-). The reaction mixture maybe diluted with water without precipitation .of the hydrolysis product. The hydrophilic'color sirably contain at least one ether oxygen atom for every 40 chain atoms or between 1 and 10 ether oxygen atoms for each 10 amide groups. The following compounds containing ether groups are among those valuable in preparing the polyamides oi the present invention:

NnO-(cn,).o om).C Nm mmcmnocnO-omomnn-um In these compounds .1: is 1, 2, 3, or 4 and one or more of the hydrogen atoms on carbon atoms may be replaced by methyl, ethyl, etc. In addition, aliphatic diamines, dibasic acids, or aminoacids having small alkoxy groups, e. g., methoxy, ethoxy, propoxy, are useful in preparing these water-sensitive polyamides.

Another useful class of intermediates for preparing water-sensitive polyamides are those containing intralinear tertiary nitrogen groups such as the following:

In these compounds R is a small alkly group, e. g., methyl, ethyl propyl, and x is 2, 3, or 4.

In cases where the polyamide chain contains no water solubilizing group (ether or terytiaryamino group) or an insufficient number to cause a satisfactory solubility and permeability, the introduction of such groups by reaction with formaldehyde and active hydrogen compounds such as alcohols, amides, ureas. etc.. is possible. Suitable alcohols include methyl, ethyl, propyl, betamethoxy-ureas, ethyl, etc.

A high water solubility of the original polymer 'beta-naphthylamine; (5) 2,4-dihydroxyquinoline; (8) p-nitrobenzylcyanide; (7) diketohydrindene; (8) malonamides, e. g., ethyl-N- phenylmalonamate, N-N-diphenylmalonamide;

o (9) phenacylpyridinium bromide: (10) hydroxycyanoacetanilide, cyanoacetic 5 of color photography.

does not prevent its use in the preparation of 5 the color-formers of the present invention, since the introduction of dye intermediate nuclei may decrease the cold water solubility to a point where the coated films are no longer softened excessively in water. If the hydrophilic color former does not have sufllciently high water sensitivity or solubility, this can be improved by the introduction of solubilizing groups. For example, the carboxylic or sulfonic acid group can be introduced by reaction with formaldehyde and an ester of a hydroxy acid, followed by hydrolysis, or by the use of a dye intermediate nucleus containing such solubilizing groups. Any of these solubilizing groups can be introduced either before or after introduction of the color-forming groups into the polymer.

In the method of preparing these polyamide color-forming binding agents employing formaldehyde to connect the color formers to the In addition to the color-forming groups of the above examples, many of the other well-known coupling component groups may be employed. Thus, the dye intermediate nucleus may be any aromatic, phenolic, or amino compound having a coupling position available ortho or para to the activating group, or any active methylene compound, i. e., a compound having a -CH2 group activated by two unsaturated groups taken from the class of 3 methyl 5 pyrazolone, l-p-chlorophenyl- 3 methyl 5 pyrazolone, 1 phenyl-3-carbox -5- pyrazolone, 1-m-suliophenyl-3-methyl-5-pyrazolone; (3) indoxyl and thioindoxyi'; (4) N-homophthalylamines, e. g., N-homophthalylaniline, N-

homophthalyl-n-dodecylamine, N-homophthalylpyridin ethyl ester.

The color yielding elements of this invention are not limited in their utility to any one process They may be used with other color coupling developing agents than those specifically described in the examples. The d1 amino aryl compounds such as para-phenylenediamine and its substitution products are preferred. These developers may be substituted in one amino group as well as in the ring, preferably the former, to constitute compounds such as .the monoand di-alkyl arylenediamines, including the monoand di-alkyl naphthylenediamines, alkyl phenylenediamines and alkyl toluylenediamines. The compounds, of course, must have one free primary or unsubstituted amino group which enables the oxidation product of the developer to couple with the colorforming compounds. As examples of developers of the class described, there may be mentioned p amino diethyl aniline, 1,4-naphthy1enediamine, 4-die'thylamine-i-naphthyl-amine. The salts of the bases which may be organic or inorganic are, in general, more soluble and more stable than the free bases. The hydrochlorldes and sulfates have great utility in preparing the developing solutions.

polyamide, the formaldehyde may be in any form. 10 The hydrophilic polyamide dye intermediates Thus, it can be used as solid paraformaldehyde, or dissolved or suspended in water or solvents for the polyamide, or as formaldehyde releasing compounds such as trloxane, hexamethylenetetramine, etc.

" atives of polyamides are also useful in many other dyeing operations. They may be incorporated in polymers or solutions 01' polymers used for spinning fibers or casting films, e. 3., cellulose and its derivatives nylons, polyesters, vinyl polymers, etc. Materials or articles containing the dye intermediate or Examples II or III when treated with diazotized p-nitroanilineo-sulfonic acid is converted to a bright yellow color and the polymeric dye, being an integral part of the materials or articles, is fast to wash-' ing and dry cleaning even when repeated many times and under drastic conditions. Similarly when the dye intermediate oi Example V is reacted with diazotized p-nitroaniline-o-sulionic acid a, blue dye is formed which is equally resistant to washing or dry cleaning. By the use of the new hydrophilic dye intermediates prepared according to this invention but using dyeforming reagents containing other dye intermediate nuclei a wide range of dyes may be formed. Alternatively the polymers may be converted to dyes by treatment with diazotized amines and the polymeric dyes incorporated in the fiber or film-forming polymer. Dyed articles prepared in this way exhibit the same high deree of wash i'astness.

The new hydrophilic polyamlde color formers are also useful in other colloid silver halide emulsion layers. Thus they may be dissolved in water or aqueous solutions of water-miscible solvents and incorporated in gelatin-silver halide emulsions. The new color-formers being themselves binding agents and highly polymeric do not under these conditions wash out of or migrate in the gelatin. etc., emulsions.

What is claimed is:

l. A hydrophilic synthetic linear polyamlde dye intermediate having a plurality of extralinear dye intermediate nuclei attached to an amide nitrogen atom of the polyamlde chain of atoms through an unsubstituted methylene radical, the intralinear amide groups of said chain being separated by at least two carbon atoms, said nuclei possessing a, structure of the formula:

-(i hcird cn possessing a structure of the formula:

where x is a member of the group consisting of HO--, primary and secondary amino radicals and n is a number from the group consisting of 0 and 1, which is soluble to the extent or at least 5% g by weight in a boiling aqueous solution containing less than 50% oi ethanol.

3. A hydrophilic synthetic linear polyamide color former having the intralinear amide roups in the polyamlde chain of atoms being separated 10 by at least two carbon atoms, and having a plurality oi extralinear color former nuclei each of which are attached to an intralinear amido nitrogen atom by a radical oi the formula CH2A, wherein A is a linkage taken from the as group consisting of a single bond, amino, amido,

sulfonamido, and ether oxygen and is attached to the color former nuclei.

4. A hydrophilic synthetic linear polyamide color former containing a plurality of colorso former-substituted intralinear amide groups of the formula I C ON-C Hr-aryl-hydroxyl said intralinear amide groups being separated by a chain of at least two carbon atoms.

6. A hydrophilic synthetic linear polyamlde color former containing a plurality of colorq 40 former-substituted intralinear amide groups of the formula -CONCHzpyrazolone, said intralinear amide groups being separated by a chain of at least two carbon atoms.

7. A hydrophilic synthetic linear polyamlde color former containing a plurality of color former units of the structure NH(CH2)|O (CHI)I0 (CHDQNC 0 (C iMC O-- DAVID MALCOLM MCQUEEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 0 Number Name Date 2,307,899 Frohlich et al. Jan. 5, 1943 2,179,231 Schneider Nov. '7, 1939 Certificate of Correction Patent No. 2,428,108.

DAVID MALCOLM McQUEEN It is hereby certified that errors appear in the (printed specification of the above numbered patent requiring correction as follows: olumn 2, line 42, for the word coumarones read coumaronones; column 7, line 41, for terytiary" read tertiary; and that the said Letters Patent should be read with these correctmns therein that the same may conform to the record of the casein the Patent Oflice.

Signed and sealed this 2nd day of March, A. D. 1948.

September 30, 1947.

THOMAS F. MURPHY, I

Assistant Commissioner of Patents. 

